This study will evaluate the importance of esophageal abnormalities in patients with recurring chest pain documented to be "non-cardiac" in origin. The study will attempt to evaluate both the incidence and causal relationship of esophageal motility abnormalities to chest pain and also some possible mechanisms of esophageal pain production. Initial studies will evaluate the range of esophageal motility findings in 100 normal subjects in all age groups to better define the "abnormal" response. Using these criteria, evidence for abnormal esophageal motility will be sought in a large group of patients with "non-cardiac" chest pain and also in patients with known cardiac abnormalities. An apparatus for prolonged (up to 72 hours) monitoring of intraesophageal pressure and pH will be developed to ascertain whether specific esophageal motility abnormalities can be correlated with chest pain events in these patients. A system for direct on-line computer evaluation of esophageal motility findings will be developed for more rapid and objective evaluation of manometric findings. Long term follow-up of patients identified as having esophageal chest pain will be obtained through the establishment of a chest pain clinic. The mechanism(s) of esophageal pain production will be studied through a number of approaches. The effects of established methods of provoking esophageal chest pain will be evaluated during constant manometric monitoring in the patient groups discussed above. These techniques will include both acid infusion into the esophagus and intravenous injections of edrophonium. Balloon distention in the distal esophagus will be evaluated in normal volunteers and in groups of patients with esophageal motility abnormalities. Because of the possible emotional and stress relationship of chest pain produced by the esophagus, personality profiles and motility response to induced stress will be evaluated in these patients.